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Small Engines (Lawn Mowers, etc.)/Craftsman backpack leaf blower won't start


QUESTION: I bought the backpack leaf blower at Sears a couple of years ago and pretty much only use it once or twice a year for the fall leaf pickup.

Craftsman 30cc  model 794991
Engine model  316.794991
2 cycle

Use to work great.  Now I can't get it to start.  Took out the spark plug and cleaned it, looked fine.  Still wouldn't start.  thought I'd run to Sears for a new spark plug.

I read some reviews on the Sears Product website and several customers spoke about a "short block" problem when they had starting problems.

Appreciate your thoughts.

ANSWER: Short block usually refers to a new piston and cylinder...basically an engine overhaul.

Here's where I would start.  Get a small squirt bottle, like a diner style ketchup bottle with the long pointy/tapered tip.  I get mine at Wal-Mart for less than $1.00.

Get some fresh fuel and oil mix.  Remove air filter cover.  Squirt a little of the fresh/new fuel/oil mix into the carb and see if the engine will try to start.  If it does then you most likely have a carb/fuel issue.  

If it does not try to start replace the spark plug and try the same and then try to start.

If it still does not start find a friend or rent a compression gauge from an auto parts store and check the engine compression.

Let me know if the engine tries to start by priming.

---------- FOLLOW-UP ----------

QUESTION: First thank you for your thoughts, much appreciated.

I like the squirting into the carb idea, but it still would not start.  I took the spark plug out and it seemed to be a bit moist. Unfortunately I did not have a new spark plug (25 miles to Sears).  Though the unit is a couple of years old, it was only use a couple of times to blow leaves. Plus I have thoroughly cleaned the spark plug, hard to image, though would not be surprised, the spark plug to be faulty.

Anyway, took the unit to a local STIHL service center.  We are in southwest Michigan and they said that all the gasoline sold here is 10% ethanol. If it sits around for more than two months (12 months in my case) the ethanol starts to separate so you get a high concentration of alcohol.  The alcohol attacks the rubber/synthetic diaphragms in the carb/fuel pump making them inoperatable. They said 8 out of 10 small engine start issues they get are of this nature.

I left the blower with them to take a look at it.

They sell a liter can of premix fuel with no alcohol for $8. They recommend if your small engine is going to sit around for more then a couple weeks, one should winterize it with this premix.

Thanks again,


Their dialogue sounds accurate as we see the same issue in CO with the ethanol fuels.  In fact, in the past couple of years we have seen an increase in how fast the carburetor and fuel lines are deteriorating...we rebuild a lot of carbs and replace lots of fuel lines these days.  Usually if the engine starts by priming then we pretty much know the carb parts need replacing.

The $8 per can comes to about $32 per gallon but if you only use the blower a couple of times per year the non-ethanol can fuel is worth it.  We are starting to sell a lot of it to customers and they have been happy as their equipment starts when they want to use it and they don't have to pay $60-70 each year to rebuild the carb and have the fuel lines replaced.

I'm not sure how much more ethanol blending will be done but if the government mandates higher percentages there will be lots of older equipment that may not run such as my older motorcycles, outboard boat engines, ATVs...the list goes on and on.

If you don't mind would let me know what the shop does to fix your blower and how much it costs.


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Eric A. Jones


Lawnmower Repair . Certified Master Service Technician from B&S. Have 23 years experience on B&S, Lawn Chief, Weed Eater, Echo, Peerless, Wheel Horse, Snapper, Atlas, MTD, McCulloch, Homelite and many other numerous brands. Specialize in electrical repair.


Born and raised in the midwest. Started tinkering with engines when I was about 14 on my Suzuki RM-80. I began lawn mower repair at a small hardware store. I knew absolutely nothing. I read lots of repair manuals and met an older fellow who taught me many lessons. I continued working on small engines through high school and paid my way through college working on mowers at the same hardware store. Decided to get away from the midwest and mower repair so I joined the Air Force. I repaired air traffic control electronic equipment and ended up in Hawaii where I got a part time job at Small Engine Clinic. I gained a lot of experience from the Small Engine Clinic and had a blast repairing small engines. I then took the Briggs and Stratton Master Service Technician test and earned my MST. I then traveled to Wisconsin where I attended the factory update training seminar and received formal training. Continued working on mowers part time as I completed 20 years of military. Retired from the military on a Friday and continued in the lawn and garden industry the next Monday.

MAS Aerospace Operations BA Mathematics AAS Electronic Communications AAS Electronic Technology

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